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Method for preparing aluminum nitride ceramics by aid of ammonium fluoride which is used as additive

A technology of aluminum nitride ceramics and ammonium fluoride, applied in the field of preparation of aluminum nitride ceramics, can solve the problems of introducing new impurities, etc., and achieve the effects of improving purity, avoiding AlON impurity phase, and promoting densification

Active Publication Date: 2016-08-10
WUHAN UNIV OF TECH
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

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Problems solved by technology

[0004] The purpose of the present invention is to overcome the technical difficulty that existing oxide additive introduces new impurity in AlN ceramic sintering process, adopts ammonium fluoride (NH 4 F) as an additive to reduce the AlON impurity phase in AlN ceramics without introducing other impurities, and at the same time promote the densification of AlN ceramics

Method used

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  • Method for preparing aluminum nitride ceramics by aid of ammonium fluoride which is used as additive
  • Method for preparing aluminum nitride ceramics by aid of ammonium fluoride which is used as additive
  • Method for preparing aluminum nitride ceramics by aid of ammonium fluoride which is used as additive

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Effect test

Embodiment 1

[0027] The ammonium fluoride crystal particles are ground in a corundum mortar to obtain fine and uniform ammonium fluoride powder with a particle size of 1.9 μm; the ammonium fluoride powder and aluminum nitride powder with a particle size of 0.5 μm Mix according to the mass ratio of 0.24:1, fully grind evenly in a corundum mortar, and obtain a mixed powder with a particle size range of 0.5-1.8 μm; put the mixed powder into a high-temperature graphite mold, and place the mold in plasma activation Sintering was carried out in a sintering furnace under the following sintering conditions: sintering temperature 1600°C, holding time 4min, sintering pressure 40MPa, sintering atmosphere was nitrogen, and the final sample was aluminum nitride ceramics.

[0028] The density of the obtained aluminum nitride ceramic sample is 98.2% as tested by the Archimedes drainage method, and the oxygen content is 1.23% as measured by an oxygen, nitrogen and hydrogen combined detector.

Embodiment 2

[0030] The ammonium fluoride crystal particles are ground in a corundum mortar to obtain fine and uniform ammonium fluoride powder with a particle size of 1.7 μm; the ammonium fluoride powder and aluminum nitride powder with a particle size of 0.5 μm Mix according to the mass ratio of 0.24:1, fully grind and evenly in the corundum mortar to obtain the mixed powder with a particle size range of 0.5-1.6μm; put the powder into a high-temperature graphite mold, and place the mold in plasma activation sintering Sintering was carried out in a furnace under the following sintering conditions: sintering temperature 1800°C, holding time 3min, sintering pressure 35MPa, sintering atmosphere was nitrogen, and the final sample was aluminum nitride ceramics.

[0031] The density of the obtained aluminum nitride ceramic sample is 99.3% as tested by the Archimedes drainage method, and the oxygen content is 0.97% as measured by an oxygen, nitrogen and hydrogen combined detector.

Embodiment 3

[0033] The ammonium fluoride crystal particles are ground in a corundum mortar to obtain fine and uniform ammonium fluoride powder with a particle size of 1.9 μm; the ammonium fluoride powder and aluminum nitride powder with a particle size of 0.5 μm Mix according to the mass ratio of 0.30:1, fully grind it evenly in a corundum mortar, and obtain a mixed powder with a particle size range of 0.5-1.8 μm; put the powder into a high-temperature graphite mold, and place the mold in plasma activation sintering Sintering is carried out in a furnace under the following conditions: sintering temperature 1600°C, holding time 5min, sintering pressure 30MPa, sintering atmosphere is nitrogen, and the final sample is aluminum nitride ceramics.

[0034] The density of the aluminum nitride ceramic sample obtained by the Archimedes drainage method is 98.4%, and the oxygen content is 0.60% as measured by an oxygen, nitrogen and hydrogen combined detector.

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Abstract

The invention discloses methods for preparing aluminum nitride ceramics, and relates to a method for preparing aluminum nitride ceramics by the aid of ammonium fluoride which is used as an additive. The method particularly includes respectively weighing ammonium fluoride powder and aluminum nitride powder according to a mass ratio of (0.24-0.36):1, and then sufficiently uniformly grinding the ammonium fluoride powder and the aluminum nitride powder in a corundum mortar to obtain mixed powder; filling molds with the mixed powder, arranging the molds in a plasma activated sintering furnace and densifying the mixed powder under the conditions of the sintering temperatures of 1600-1800 DEG C, the heat preservation period of 3-5 min and the sintering pressures of 30-40 MPa in nitrogen atmosphere to obtain the aluminum nitride ceramics. The method has the advantages that the ammonium fluoride is used as the additive, accordingly, the technical difficult problem that new sundries are introduced into existing aluminum nitride ceramics by existing oxide additives in aluminum nitride ceramic sintering procedures can be solved, generation of impure phases such as AlON can be effectively reduced in sintering procedures, and other impurities can be prevented from being introduced into the aluminum nitride ceramics; ceramic densification can be promoted, and accordingly the high-purity and high-density aluminum nitride ceramics can be prepared by the aid of the method.

Description

technical field [0001] The invention relates to the purification and sintering technology of aluminum nitride ceramics, in particular to a preparation method of aluminum nitride ceramics with ammonium fluoride as an additive. Background technique [0002] In recent years, aluminum nitride (AlN) ceramics have become a new generation of insulating materials due to their high thermal conductivity, high insulation, low dielectric constant and dielectric loss, good mechanical properties and thermal expansion coefficients that match semiconductor materials The first choice for heat dissipation packaging materials and semiconductor substrate materials, and only high-purity, high-density AlN ceramics have excellent comprehensive properties. However, on the one hand, because the Al-N bond in AlN has a high covalent bond composition, high melting point, small self-diffusion coefficient, and low sintering activity, it is difficult to sinter and densify AlN powder. On the other hand, s...

Claims

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Application Information

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IPC IPC(8): C04B35/581C04B35/622C04B35/63
CPCC04B35/581C04B35/622C04B35/6303C04B2235/445C04B2235/74C04B2235/77
Inventor 王传彬王丹丹李美娟王广阳沈强张联盟
Owner WUHAN UNIV OF TECH